Robotic turntable

ABSTRACT

A plurality of robots are positioned on a rotatable table for transporting parts to be processed through a plurality of work stations positioned around the periphery of the table. Each robot can carry a workpiece from one work station to the next. The rotation of the table moves the robot from one workstation to the next while carrying a part to be processed. Each robot can be independently movable relative to the other robots and each robot can be independently movable relative to the table. Each robot can include a welder for processing the workpiece independent of the workstation or during movement between work stations. Each robot can carry a plurality of differently configured workpieces between the work stations.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of prior application Ser. No.09/813,766 for a ROBOTIC TURNTABLE, filed on Mar. 21, 2001 now U.S. Pat.No. 6,435,397 which claimed the benefit of prior provisional applicationSer. No. 60/197,614 filed Apr. 18, 2000.

FIELD OF THE INVENTION

The present invention relates to a plurality of robots positioned on aturntable at spaced locations along the periphery, where the turntableis movable in rotation to predetermined angular positions independentlyof movement of the individual robots disposed thereon.

BACKGROUND OF THE INVENTION

A modular robotic finishing work center is disclosed in U.S. Pat. No.4,644,897. The patent discloses an elevated platform with a turntablemounted thereon which is rotatable about a vertical axis, and a robotmanipulator fixedly mounted relative to the vertical axis, wherein theturntable ends are rotatable through a circular path where at least partof the path includes a partially protected booth for collecting paintresidue and overspray. The robot manipulator has a movable arm and sprayapplicator capable of movement along a limited range so as to provide apredetermined envelope of possible work areas for spray finishing, wherea portion of the turntable end path and at least a portion of the spraybooth are included within this envelope.

A tool turntable for a manufacturing system is disclosed in U.S. Pat.No. 5,186,304. The production line manufacturing system includes aprogrammable multi-position rotatable unit that can be used in each ofthe work stations to accommodate both changes in workpieces to beprocessed and tools. The rotatable unit includes a four-positionhorizontally arranged fixture table including four vertically arrangedfixtures movably mounted thereon. A precision locator key on each of thefixtures positions each individual fixture on the table and also servesas a positive fixture stopped in the work position.

SUMMARY OF THE INVENTION

It would be desirable in the present invention to provide a turntable ora carousel with a plurality of robots positioned thereon in peripherallyspaced locations with respect to one another for movement about avertical axis of the turntable while allowing independent movement ofeach of the individual robots positioned thereon. The apparatus formanufacturing parts according to the present invention can include aturntable having an outer periphery and a centrally located axis ofrotation, a plurality of robots positioned at peripherally spacedlocations about the turntable with respect to one another forindependent movement with respect to one another and with respect tomovement of the turntable, and a control system for controlling andsynchronizing independent individual movements of the robots withrotation of the turntable to move each individual robot from one workstation at a first angular position to another work station at a secondangular position.

Other objects, advantages and applications of the present invention willbecome apparent to those skilled in the art when the followingdescription of the best mode contemplated for practicing the inventionis read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The description herein makes reference to the accompanying drawingswherein like reference numerals refer to like parts throughout theseveral views, and wherein:

FIG. 1 is a simplified plan view of a robotic turntable or carouselaccording to the present invention for manufacturing parts; and

FIG. 2 is a side elevational view of a robotic turntable according tothe present invention including a plurality of robots individuallyoperating with respect to different work stations on opposite sides ofthe turntable.

DESCRIPTION OF THE PREFERRED EMBODIMENT

An apparatus 10 according to the present invention provides for themanufacturing of parts 12 by a plurality of robots 14 positioned on aturntable 16 for rotation about an axis 18. The robots are positioned atdifferent locations spaced along the outer periphery of the turntable16. In the illustrated embodiment, there are an equal number of robots14 to the number of work stations 20 positioned around the periphery ofthe turntable 16, although an equal number of robots to work stations isnot required to practice the present invention. By way of example, andnot limitation, the present invention will be described in detail withrespect to the manufacture of particular parts 12, such as a side panelsub assembly of a motor vehicle.

Referring now to FIG. 1, the turntable 16 is illustrated having eightrobots 14 a, 14 b, 14 c, 14 d, 14 e, 14 f, 14 g, 14 h disposed at evenlyspaced angular positions around the outer peripheral edge of theturntable 16. The robots 14 a-14 h are independently movable withrespect to one another, and are movable independent of movement of theturntable 16. When the turntable 16 is disposed at a first angularposition, such as that illustrated in FIG. 1, each robot 14 is capableof performing various independent work cycles at the individual workstation 20 corresponding to its current location. By way of example andnot limitation, in the position illustrated in FIG. 1, the robot 14 a ispositioned at work station 20 a for unloading parts that have beenprocessed. After unloading a part, the turntable 16 can be rotated aboutthe axis 18 to now position the robot 14 a at the position previouslyoccupied by robot 14 b. In this position, the robot has access to a toolchange work station 20 b in order to provide the opportunity to changethe tooling as required for the particular part to be processed next.

After completion of the tool change, if any, at work station 20 b, theturntable 16 can be rotated again about the axis 18 to move the robot 14a from the position previously shown for robot 14 b to the positionpreviously shown for robot 14 c. When in this position, the robot canpick up a part to be processed at the part loading fixture 22 at workstation 20 c. Preferably, the fixture 22 located at the work station 20c is an indexing part load fixture 22 c capable of positioning aplurality of fixtures corresponding to the desired body style and modelto be processed through the work station 20 c. In its most preferredconfiguration, the indexing fixture 22 c includes four differentfixtures positioned on four major surfaces of a rectangular fixturerotatable about a horizontal axis to position one of the four majorsurfaces in an upright ready position for receiving parts to be loadedonto or picked up by the robot at work station 20 c.

After the robot has retrieved the part to be processed from the workstation 20 c, the turntable 16 is rotated about the axis 18 to bring therobot 14 a into the position previously illustrated for robot 14 dcorresponding to work station 20 d. At work station 20 d, the robot 14 apositions the part 12 into the fixture 22 d allowing additional work tobe performed on the part. The fixture 22 d is preferably an indexingpart fixture similar to fixture 22 c. The fixture 22 d preferably hasfour major surfaces with different fixtures for various models and bodystyles to be processed. The fixture is rotatable about a horizontal axisto bring a selected one of the four major surfaces into an upright readyposition for receiving the next part to be processed. The additionalwork can include the attachment and assembly of various sub componentsto the part, or the clamping and welding of various components atdifferent positions on the part, or any other automated processingrequired with respect to the particular part being processed through theapparatus 10 according to the present invention. The processing caninclude assembly and/or welding by additional robots 24 a-24 d disposedat work station 20 d. One or more robots 24 can be positioned at thework station 20 d as required for the particular part processing to takeplace at the particular work station. After the processing of the partis completed at work station 20 d and the robot 14 a retrieves the partfrom the fixture 22 d, the turntable 16 is rotated about the axis 18 tomove the robot 14 a to the position previously illustrated for robot 14e. At this position, additional processing can take place as requiredfor the particular part. By way of example and not limitation, theillustration shows a respot work station 20 e for welding areas of thepart inaccessible while resting in the fixture 22 d of work station 20d. A respot welder 26 can be positioned at each respot work station,such as welder 26 e at work station 20 e.

After respotting has been completed at the work station 20 e, theturntable 16 can be rotated about axis 18 to position the robot 14 a inthe position previously shown for robot 14 f. The part can be loaded bythe robot into the fixture 22 f at the work station 20 f. The fixture 22f preferably can be an indexing part fixture similar to 22 d and 22 cpreviously described. In the most preferred configuration, the indexingpart fixture 22 f is provided as a rectangular fixture having four majorsurfaces with different fixtures for the various models and body stylesto be processed through the apparatus 10 according to the presentinvention. The rectangular fixture is rotatable about a horizontal axisto bring a selected one of the four major fixture surfaces into anupright ready position for receiving the part to be processed. Theprocessing at the work station 20 f can include assembly of additionalsub components to the primary part being assembled, or additionalclamping and welding of various portions of the part to one another.Additional robots 26 a-26 d can be provided at the work station 20 f toperform the assembly or welding operations as required.

When processing of the part has been completed at the work station 20 f,the turntable 16 can be rotated about the axis 18 to position the robot14 a at the position previously illustrated for robot 14 g. Additionalprocessing of the part can take place at work station 20 g when therobot is in this position. By way of example and not limitation, arespot welding apparatus 26 g can be provided to weld portions of thepart 12 being assembled that could not be accessed while the part waspositioned in the fixture at work station 20 f.

After respotting has been completed, the turntable 16 can be rotatedabout the axis 18 to position the robot 14 a at the position previouslyillustrated for robot 14 h. At this position, the part can be subjectedto additional processing, by way of example and not limitation, such asadditional respot welding by a respot welding apparatus 26 h at workstation 20 h. When the additional processing is completed at workstation 20 h, the turntable 16 can be rotated about the axis 18 to againbring the robot 14 a to the position illustrated as 14 a in FIG. 1 wherethe processed part can be unloaded at the work station 20 a.

While the invention has been described in detail with respect to asingle robot 14 a being rotated through the various work stations aroundthe periphery of the turntable 16, it should be apparent to thoseskilled in the art that the additional robots 14 b, 14 c, 14 d, 14 e, 14f, 14 g, 14 h positioned on the turntable 16 perform the same operationsat the various work stations while rotated through the various workstation positions 20 b, 20 c, 20 d, 20 e, 20 f, 20 g, 20 h, and thatwork is simultaneously performed at each work station by each of therobots 14 a-14 h prior to the turntable being moved to transfer therobots 14 a-14 h and parts carried by the robots 14 a-14 h to the nextwork station 20 a-20 h in the processing system.

Referring now to FIG. 2, a cross-sectional elevational view is shown ofthe robots 14 d, 14 f on the turntable 16 according to the presentinvention through work station 20 d and work station 20 f. As previouslydescribed, the robots 14 d and 14 f can transport workpieces 12 to thework station 20 d and 20 f respectively and can load the parts into acorresponding fixture 22 d, 22 f for the particular part to beprocessed. Each of the indexing fixtures 22 d, 22 f at the work stations20 d and 20 f can be in the form of a rectangular fixture having fourmajor surfaces with different fixture configurations for the variousbody styles and models to be processed through the work stations. Eachof the fixtures 22 is rotatable about an axis 30 to position the desiredfixture in the upright ready position for receiving the part to bedelivered by the corresponding robot presently positioned at that workstation. Welders 32 can be positioned above each of the robots 14, ascan best be seen in FIG. 2 where welder 32 d is positioned above robot14 d and welder 32 f is positioned above robot 14 f. The welders 32positioned above the robots 14 allow additional welding to be performedduring a movement cycle of the turntable 16, or while one work stationis waiting for completion of work being performed at another workstation. In this way, additional work can be performed by the robot 14and welder 32 between cycles performed at various work stations. Thepart can be manipulated and moved as required to perform multiple weldswith the welders 32, or the respot welders 26 e, 26 g, 26 h at the workstations 20 e, 20 g and 20 h.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiments but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims, which scope is to be accorded the broadestinterpretation so as to encompass all such modifications and equivalentstructures as is permitted under the law.

What is claimed is:
 1. An apparatus for moving a workpiece along anassembly line having a plurality of workstations, the apparatuscomprising: a plurality of robots mounted for movement along a fixedpath between workstations, each robot for manipulating at least oneworkpiece; and a rotatable turntable supporting the plurality of robotsfor simultaneous movement between the plurality of workstations.
 2. Theapparatus of claim 1 wherein at least one workstation further comprises:at least one fixture for retaining each one of a plurality of differentconfigurations of workpiece to be moved through the assembly line. 3.The apparatus of claim 1 wherein each of the plurality of robots furthercomprises: means for delivering the workpiece to a fixture located atone of the plurality of workstations.
 4. The apparatus of claim 1further comprising: interchangeable means for manipulating a pluralityof different configurations of workpieces.
 5. The apparatus of claim 1further comprising: at least one welder mounted in fixed relation withrespect to each robot for movement along the fixed path, each welder forperforming a welding operation on the workpiece while being manipulatedby the corresponding robot between delivery to successive workstations.6. The apparatus of claim 1 wherein the plurality of robots are evenlyspaced from each other.
 7. The apparatus of claim 1 wherein a number ofrobots mounted along the fixed path is equal to a number of workstationspositioned adjacent to the fixed path.
 8. The apparatus of claim 1wherein each of the plurality of robots further comprises: means formanipulating the workpiece relative to the rotatable turntable.
 9. Theapparatus of claim 1 wherein each of the plurality of robots furthercomprises: means for manipulating the workpiece relative to at least oneother robot, the other robot mounted along the fixed path and associatedwith at least one of the plurality of workstations.
 10. The apparatus ofclaim 1 further comprising: a single movable platform supporting theplurality of robots for movement along the fixed path betweenworkstations.
 11. A method for moving a workpiece along an assembly linehaving a plurality of workstations, the method comprising the steps of:manipulating each workpiece to be processed with one of a plurality ofrobots, each robot mounted for movement along a fixed path betweenworkstations; and supporting the plurality of robots on a rotatableturntable for simultaneous movement between the plurality ofworkstations.
 12. The method of claim 11 further comprising the step of:performing at least one welding operation on each workpiece while theworkpiece is being manipulated by the corresponding robot moving theworkpiece along the assembly line between successive workstations. 13.The method of claim 11 further comprising the step of: performing atleast one welding operation on each workpiece while the robots aremoving along the fixed path.
 14. The method of claim 11 furthercomprising the step of: interchanging manipulating means formanipulating a second workpiece having a different configuration. 15.The method of claim 11 further comprising the step of: positioning atleast one fixture for retaining each one of a plurality of differentconfigurations of workpiece to be moved through the assembly line at aworkstation.
 16. The method of claim 11 wherein the manipulating stepfurther comprises the step of: manipulating the workpiece relative tothe rotatable turntable.
 17. The method of claim 11 wherein themanipulating step further comprises the step of: manipulating theworkpiece relative to at least one other robot, the other robot mountedalong the fixed path and associated with at least one of the pluralityof workstations.
 18. The method of claim 11 further comprising the stepof: supporting the plurality of robots for movement along the fixed pathbetween workstations on a single movable platform.